Antagonists of the CCR5 receptor are useful for the treatment of AIDS and related HIV infections. CCR-5 receptors have also been reported to mediate cell transfer in inflammatory diseases such as arthritis, rheumatoid arthritis, atopic dermatitis, psoriasis, asthma and allergies, and inhibitors of such receptors are expected to be useful in the treatment of such diseases, and in the treatment of other inflammatory diseases or conditions such as inflammatory bowel disease, multiple sclerosis, solid organ transplant rejection and graft v. host disease.
WO 00/66559, published Nov. 9, 2000, discloses the piperidine compound of formula I, 4-[(Z)-(4-bromophenyl)(ethoxyimino)methyl]-1′-[(2,4-dimethyl-1-oxido-3-pyridinyl)carbonyl]-4′-methyl-1,4′-bipiperidine, its acid salt (the compound of formula II) and pharmaceutical compositions comprising I and II: 
The compounds of formulas I and II are antagonists of the CCR5 receptor and are useful for the treatment of AIDS and related HIV infections. CCR-5 receptors have also been reported to mediate cell transfer in inflammatory diseases such as arthritis, rheumatoid arthritis, atopic dermatitis, psoriasis, asthma and allergies, and inhibitors of such receptors are expected to be useful in the treatment of such diseases, and in the treatment of other inflammatory diseases or conditions such as inflammatory bowel disease, multiple sclerosis, solid organ transplant rejection and graft v. host disease. Pending patent application Ser. No. 10/629,822 filed Oct. 11, 2002, which is incorporated herein by reference, discloses a novel process to synthesize the compound of formula I.
The piperazine compound of formula III, Piperidine, 4-[4-[(1R)-[4-(trifluoromethyl)phenyl]-2-methoxyethyl]-(3S)-methyl-1-piperazinyl]-4-methyl-1-[(4,6-dimethyl-5-pyrimidinyl)carbonyl, its acid salt (formula IV), and pharmaceutical compositions comprising the compounds of formulas III and IV are disclosed in WO 00/66558 published Nov. 9, 2000. The piperazine of formula III (a free-base) and its acid salt (formula IV) are disclosed therein as being useful as antagonists of CCR5 receptor. 
In view of the importance of the antagonists of the CCR5 receptor, new methods of making such antagonists are always of interest.